The present invention relates to a microprocessor-based control system for operating a gas turbine electric powerplant. The gas turbine electric powerplant uses a turbine engine, such as an aircraft engine, to operate an electric generator that produces electric power. The microprocessor-based control system provides for the proper start-up, operation, and shut-down of the gas turbine electric powerplant, as well as for monitoring and turbine overspeed control. The microprocessor-based control system allows the gas turbine electric powerplant to be operated safely, even in an unattended condition.
There are numerous situations wherein it may be desirable to use a gas turbine electric powerplant of the present invention. For example, it may be necessary to provide electric power to a remote area that is not supplied by a utility company. Electric power consuming operations that are commonly conducted in remote areas include, for example, drilling for oil and natural gas. Such operations may require more power than can be supplied by typical gas or diesel generators. When such an operation is too remote to receive power from a utility, the gas turbine electric powerplant of the present invention may be used to supply electric power to the operation. Similarly, the gas turbine electric powerplant of the present invention can be used when electric power production is required on only a temporary basis. For example, in the above-described remote drilling operation, utility power may be available, but connection costs may be prohibitive based on the short period of time during which electric power will be required. Such a situation may also occur during large-scale, remote construction projects.
The gas turbine electric powerplant of the present invention may also be used to provide backup power during interruption of electric power supplied from a utility or other source. The gas turbine electric powerplant of the present invention may be brought online in as little as 30–60 seconds, thereby preventing long periods of down time. Use of the gas turbine electric powerplant for backup power may be highly effective for commercial buildings, manufacturing facilities, hospitals, or other locations wherein a long term interruption of electric power is particularly problematic.
One or more of the gas turbine electric powerplants of the present invention may also be used in a variety of other ways by a producer of electric power. For example, an electric utility may utilize one or more of the gas turbine electric powerplants to provide load-leveling or peak shaving during periods of high demand for electric power. Utilities commonly struggle with the problem of meeting peak demand, which occurs typically at particular times of the day, and is usually more severe during certain times of the year. Peak demand is the result of consumers using more electricity at particular times of the day than at others; for example, during the waking hours as opposed to during the nighttime hours. To meet peak demand, a utility's power generating plants must typically be overdesigned—meaning that they only run near peak efficiency during periods of high demand. Therefore, for the majority of a given day, the power plant runs at a reduced output and, unfortunately, a lower efficiency. By employing the gas turbine electric powerplant of the present invention, utility power generating plants could be designed to meet only average demand while running at optimum efficiency. One or more of the gas turbine electric powerplants of the present invention could then be tied to the utility's power distribution and transmission grid, and when peak demands arise, the gas turbine electric powerplants can be operated to inject additional electric power into the grid. The control system of the gas turbine electric powerplant of the present invention can provide for automatic start-up and operation when high demand is detected. When the demand ebbs, the gas turbine electric powerplants can be shut down as needed. The portability of the gas turbine electric powerplant of the present invention also allows additional units to be set up at a utility if needed to meet increasing peak demand. Such a situation may occur when a particular area, or areas, served by a utility grows at a faster than expected rate. In this manner, both the cost of building a power generating plant and the cost of producing electricity may be reduced, while still ensuring that peak demand can be met.
The gas turbine electric powerplant of the present invention can also be used as a source of co-generation electric power. For example, the gas turbine electric powerplant may be installed at an industrial facility and tied into the facility's electric power transmission and distribution system in order to augment the electric power supplied by an electric utility company. The cost to purchase electric power from a utility may vary throughout a given day or week. For example, it is common for large industrial facilities to be limited in the amount of power they may use, or to otherwise be charged a significantly elevated price during periods of high demand. Such may occur, for example, during periods of extreme weather, when the general consumption of electric power typically increases. When such a situation exists, the industrial facility may operate one or more of the gas turbine electric powerplants to supplement the electric power it receives from the utility. In this manner, the industrial facility can avoid having to either reduce its power consumption or pay a higher cost for electric power during such periods.
The gas turbine electric powerplant of the present invention can also be used as a source of distributed power generation. As certain populated areas grow, the demand for electric power generally increases. Many times, the provider of electric power does not have the capacity to meet the increased demand. Electric utilities often form cooperatives, or otherwise enter into agreements wherein electric power may be sold and delivered between the utilities. Thus, if one utility cannot meet demand, and a second utility has excess capacity, the second utility may sell blocks of power to the first utility. The first utility may be at a disadvantage, because the cost to purchase and transfer the electric power to the area of demand may be high. The second utility is able to take advantage of its excess capacity by selling and distributing the electricity to other providers. The gas turbine electric powerplant of the present invention can be used to take advantage of growing markets, by allowing a provider to produce additional electric power that may be sold to other providers without sufficient capacity. Alternatively, the gas turbine electric powerplant of the present invention may be used by a provider to obviate the need for purchasing additional electric power from another utility. Rather, the provider may use the gas turbine electric powerplant to produce incremental electric power in small blocks, minimizing large incremental power block purchases from other utilities. The gas turbine electric powerplant can be located to provide electric power wherever it is needed. For example, the gas turbine electric powerplant may be placed at a distribution substation and tied into a utility's transmission and distribution lines.
The gas turbine electric powerplant of the present invention uses a gas turbine engine to run an electric generator. Preferably, the gas turbine electric powerplant uses an aeroderivative gas turbine engine, such as is designed for a helicopter. The turbine engine may be purchased new, or may be removed from an aircraft and retrofitted for use in the gas turbine electric powerplant. Although a variety of turbine engines may be employed, preferably the turbine engine is a turboshaft engine.
A gearbox is preferably used to reduce the output speed of the turbine engine to a predetermined value. While the turbine engine may have an internal gear reduction, an external gearbox is typically required to obtain the proper input speed to the generator. While a gearbox with a fixed speed reduction can be used, it is also possible to use a gearbox with a variable output speed. The input of the gearbox is connected to the output shaft of the turbine engine by a specialized coupling.
The output shaft of the gearbox is connected to the input shaft of an electric power generator. Rotation of the generator's input shaft and windings produces electric power that can be output to a specific load or into the power grid of an electric utility. The generator can be selected to provide the desired voltage and power output.
The gas turbine electric powerplant is designed to operate on both liquid and gaseous fuels that can provide a sufficient BTU output. Specific microprocessor-controlled fuel valves are provided based on the type of fuel that will be used to run the gas turbine electric powerplant. The fuel valves may be changed if it is desired to change the type of fuel used with the gas turbine electric powerplant. The microprocessor-based design of each type of fuel valve allows the valve to communicate with and respond to instructions from the gas turbine electric powerplant's microprocessor-based control system.
The assembled components of the gas turbine electric powerplant may reside on a common base, preferably on a transportable skid. Alternatively, a non-transportable installation may be accomplished, such as on the floor of a factory, or a concrete mounting pad. A specialized mounting frame is provided to receive and restrain the gas turbine engine. The frame is designed to maintain the centerline of the turbine engine despite the thermal expansion thereof. In transportable form, the size and weight of the gas turbine electric powerplant components and skid allow it to be transported by truck to virtually any site where electric power is needed. Therefore, the gas turbine electric powerplant of the present invention may provide a portable source of significant electric power production that may be utilized to meet a number of consumer needs.
Whatever the application, a microprocessor-based control system is provided to operate and monitor the gas turbine electric powerplant. The microprocessor-based control system automates the start-up, operation, and shutdown of the gas turbine electric powerplant. During operation of the gas turbine electric powerplant, the microprocessor-based control system monitors a multitude of powerplant conditions, such as, for example, fuel flow, various temperatures, turbine speed, and many other conditions, and makes any necessary adjustments to ensure that the gas turbine electric powerplant runs at optimal efficiency. The microprocessor-based control system is also in electrical communication with other control systems that are provided to effect the automatic shutdown of the gas turbine engine should the gas turbine engine become disconnected from the gearbox or generator. The microprocessor-based control system preferably provides for real time control and trend capabilities, based on the monitored conditions and on user settings. An operator interface is provided to allow for, among other things, the input of set points and the viewing of powerplant conditions.